[geubrina]

I have several kind of ores.

I have the green stone, which is most probably is copper ore. So, I make powder of it and mix it with HCl and H2SO4, separately in different beaker glass. The color turns blue. Then I add Na(OH) and there are solid black and the bottom. From this process, I can get CuO, which is black and confirm that the ore has copper in it.

The problem happen when I try to identify lead from unknown ore. The iron ore and lead ore is very different. And also, usually, there is significant zinc content in the ore.
After I add the HCl and H2SO4, there is white color solution, like milk. And there is white, fine solution at the bottom, then.
I did not know what and how is the better way, ... Pls kindly assit me.

[Arkcon]

Ah ... the old wet chemistry tricks.  Ok, I'll bite:

If the white solid is soluble in nitric acid, and after drying and redissolving in water, gives a white precipitate with HCl, it is lead, or silver or mercury.  Lead gives a fine precipitate with this method, silver's is distinctly floculent, like a snow globe.  IIRC, and I may be totally wrong here, mercury's white precipitated chloride gradually becomes gray over a period of days.  Long story short, white precip with HCl that persists is lead.

Iron is pretty easy too, do a google for spot tests, or look in the chemistry library for an old yellowing text on analytical chemistry.

The zinc may be a problem, as I recall, many other things may interfere with a spot test.

'Course, if you really care what's in your rock, you chip off a crumb and send it to an analytical lab.  For a couple hundred UD$, they submit it to ICP spec and tell you all the elements to 4 decimal places.

[Arkcon]

A similar topic has come up elsewhere, the discussion there has a good HTML link and two fairly straightforward PDF files to follow.

http://www.chemicalforums.com/index.php?topic=21759.0;topicseen